> //附上程序 简单的迭代实现 不过试了很多参数才AC
> #include<stdio.h>
> #include<string.h>
> #define MaxN 21
> #define Profit 1.01
> 
> int n;
> double map[MaxN][MaxN];
> double arb[MaxN][MaxN];
> int way[MaxN][MaxN][MaxN];
> int from,to,len;
> 
> int init()
> { int i,j;
>  if (scanf("%d",&n)==EOF) return 0;
>  for (i=0; i<n; i++)
>   for (j=0; j<n; j++)
>    {if (i==j) map[i][j]=1; else scanf("%lf",&map[i][j]);
>     arb[i][j]=map[i][j]; way[i][j][0]=j;
>    }
>  return 1;
> }
> 
> void search()
> { int i,j,k,h;
>   double tmp[MaxN][MaxN];
>   int tmpw[MaxN][MaxN][MaxN];
>  from=-1; to=-1; len=-1;
>  for (j=0; j<n; j++)
>   for (k=0; k<n; k++)
>    if (arb[j][k]*map[k][j]>Profit)
>     {from=j; to=k; len=0; return;}
>  for (i=1; i<=n-2; i++)
>   {memcpy(tmp,arb,sizeof(arb));
>    memcpy(tmpw,way,sizeof(way));
>    for (j=0; j<n; j++)
>     for (k=0; k<n; k++) arb[j][k]=-1;
>    for (j=0; j<n; j++)
>     for (h=0; h<n; h++)
>      for (k=0; k<n; k++)
>       if (tmp[j][k]*map[k][h]>arb[j][h])
>        {arb[j][h]=tmp[j][k]*map[k][h];
> 	memcpy(way[j][h],tmpw[j][k],sizeof(tmpw[j][k]));
> 	way[j][h][i]=h;
>        }
>    for (j=0; j<n; j++)
>     for (k=0; k<n; k++)
>      if (arb[j][k]*map[k][j]>Profit)
>       {from=j; to=k; len=i; return;}
>   }
> }
> 
> void show()
> { int k;
>  if (len==-1) printf("no arbitrage sequence exists\n");
>  else
>   {printf(" %d",from+1);
>    for (k=0; k<=len; k++) printf(" %d",way[from][to][k]+1);
>    printf(" %d\n",from+1);
>   }
> }
> 
> int main()
> {while(init())
>   {search();
>    show();
>   }
>  return 0;
> }
>